Input and output randomness
Also said as Pre-roll and post-roll, Input luck, Output luck
Input randomness happens before you choose, and you plan around it: the cards you were dealt, a random map. Output randomness happens after you choose and can overturn it: you aim, and then a die says whether you hit.
Input randomness rewards skill, because a good player reads the situation better. Output randomness builds tension and makes losses feel unfair. Moving a die from after the choice to before it changes who wins, with no other change at all.
Say it
“Players hate missing a 90% shot. Move the luck before the choice: show which enemies are exposed this turn, and make every shot you can take actually hit.”
Where you’ve seen it
Into the Breach shows you what every enemy will do next turn, and your attacks don't miss, so a lost building is usually your own oversight. XCOM rolls after you commit, which is how a 95% shot comes to miss at the worst moment.
Not to be confused with difficulty
Neither kind is harder as such. A game with no output luck can be brutal. The question is whether you can do anything about the luck.